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Thread: Watchmakers lathe cross sllide

  1. #11

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    Not sure if this will be of any use to you but it may be worth having a look at Rollo Elf Lathe This is a small round bed lathe with some good photos and some specs which may be useful as you ponder solutions to your problem...
    best of luck
    ..Mike,,,

  2. #12

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    firewizerp's Tools
    I agree withChrisB257 the only concerns I would have is with the polymorph deforming and or flexing, I've used it on several occasions and love the stuff, but at around 108-112 degree F it starts to soften. My shop is not air conditioned and summer temps avaverage 100+ so may be my problem. But if you are in an high temp environment its something to consider

  3. #13
    ncollar's Avatar
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    Stirlinglad
    I've looked at the Wolf Jahn lathe in that site and that is the cross slide I am going to build. I tried to put out some feelers for dimension to find no help. I will pull out my scale rules and put some numbers to it that way. It will be modeled just like Wolf Jahn. I do not foresee any problems. Fine grain cast iron is a pleasure to cut and work. I feel it will be a lot of shaper work and always enjoy running it.
    Thanks for all.

  4. #14
    kngtek's Avatar
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    Hi Britannicus

    Existing Home-Built Lathe Slide Rest Designs
    Four home-built metal slide rest designs can be downloaded from within the web link listed below. These might help in conceptualizing your compound slide options.

    How-To Documents/Articles - My CMS
    -Item no. 1 - How to Build a Lathe, author: John Mold, Model Engineer magazine, aug 1965 issue - This is a zip file; the slide rest is detailed on unzipped pdf file no. 4 of 6
    - Item no.18 - Metal Turning Lathe Built From Stock Parts, Popular Mechanics magazine, april 1959 issue, author Frank Beatty
    - Item no. 61 - Drill Press Compound Slide.pdf, author: W.H. Grubb, Home Built-Power Tools, date ?
    - Item no. 88 - Lathe-Modelling1.pdf, author: w.r. bell, source ?, date ?

    Lathe Bed Slide Rest Mounting Options
    - I believe that a Polymorph mount won't be rigid enough and will inevitably distort and/or wear resulting in inaccurate work.
    - A better (metal) option might be to purchase a second-hand Pultra 8/10 hand rest assembly, remove the top hand rest, then mount your home-fabricated slide rest to the base. One was advertised on ebay.co.uk a few days ago (gone now).
    - An even better option would be to abandon the home-built slide plate options and buy a micro lathe.

    Your initial thread posting shows a Pultra 8 (or 10mm?) collet Watchmakers Lathe. The website Lathes suggests that this lathe features a 50mm centre-to-bed distance, a Geneva style circular bed with a flat back ("D" shape), and is equipped with a headstock, tailstock, and bed clamp with a tip-over hand rest. As I understand it, this style of lathe was intended primarily for watch repair and simple lathe functions. I don't believe that a compound slide rest was ever sold for this model. Only the WW-style Pultra models equipped with a top T-slot were fitted with compound slides.

    In my experience with micro lathes, a compound slide needs to have the following features to achieve repeatable accuracy: metal-to-metal attachment to the lathe bed (preferably) via solid metal dovetail sliders, micro-adjustable longitudinal and transverse movement, gibs (cross slide & saddle) to minimize backlash (and adjust for wear) and top T-slot(s) for attaching accessories. This won't be possible with a non-metallic Polymorph base and the fabricated angle sliders you propose.

    If your intent is to use your lathe for general lathe work (and not just for watch repairs) then you would be better served by a micro lathe with say a 3.5" (90mm) minimum centre distance, factory-equipped with a compound slide. There are several good lathes of this type available at reasonable cost e.g. Sherline, Taig, Unimat, Cowell. I have two Sherline lathes: a 40 year old manual and an 8 year old CNC. With few exceptions, factory accessories fit both, although the newer one is more accurate. Even so, I can still achieve 0.001" turning accuracy with the older one.

    British master clockmaker John Wilding offers the same opinion about a 3-1/2" lathe being more useful than a 8mm watchmakers lathe on page 1 of his book "USING THE SMALL LATHE and its special applications for clockmaking and repairing" 2001.

    I hope you take my comments as being constructive and not critical.

    Best wishes, Gary (kngtek)
    Calgary, AB, Canada

  5. #15
    Toolmaker51's Avatar
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    Toolmaker51's Tools
    All these pose viable solutions. Without milling though, a properly fit dovetail is a full task, especially in aluminum which will certainly require a gib.
    I'd recommend linear guides; reasonable cost, accurate, compact, easily assembled. Couple that with choice [or both] of English or Metric feedscrew. The D bed 'carraige' should be split on one side for clamping in position. There the flat is a natural, preserving toolrest height to centerline in the most dependable manner.
    Last edited by Toolmaker51; 02-12-2017 at 08:57 AM.
    Sincerely,
    Toolmaker51
    ...we'll learn more by wandering than searching...

  6. #16
    Britannicus's Avatar
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    Britannicus's Tools
    Hi All,

    Such a great response to my initial post - I want to thank you all for your helpful advice. I'm re-working the solution a bit taking into account all of your comments and I will post how I get on - great feedback and much appreciated

  7. The Following 2 Users Say Thank You to Britannicus For This Useful Post:

    PJs (02-16-2017), Toolmaker51 (02-16-2017)

  8. #17
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    Britannicus's Tools
    Thanks for that - I have to say I'ma fan of epoxy resins too.

    Polymorph is easy, but as you say not as strong as epoxy - as for modulus etc. I don't have technicals on it, but it compares to Nylon in most respects. In this case I thought it a better fit, because a) not prone to cracking with vibration b) it mould really well, and if you get it wrong, you can heat it up and try again c) It slides really well.

    As a result of this thread I'm rethinking a bit - so will share the results.

  9. #18
    ncollar's Avatar
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    Britannicus
    Thank you for starting the thread. I have the subject in other sites with very little response, it is almost if you should buy what you need. But they were more to the clock world. I was hopeful someone would at least give some dimensions, but here again the same thing. Good luck with your build, I'll be watching.
    Nelson

    Many years ago I bought a South Bend Lathe to find that anything with that name on it is worth big bucks. To be able to use it I've made the steady rest and several things that would have required a mortgage to buy. I guess just a rant of mine.

  10. #19
    Britannicus's Avatar
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    Britannicus's Tools
    Hi Ncollar,

    I so feel your pain !! I have this theory that if Thomas Mudge and Harrison could invent and build their own toolsets in the 1700's - I should be able to adapt designs with modern tools, power and materials. Not only is "vintage kit" expensive, it's difficult to tell if it's of a reasonable quality.

    I just posted a multi-purpose press drill, staking tool that I built as well. I'm now working on a push lever tailstock for my lathe and of course the cross-slide, though I'm changing that design as I had some inspiration from my "drill stand". micro drilling / milling machine and watchmaker's press

    there was a lot of discussion round this when I posted to the NAWCC forum, which has given me a moment to pause on the design and make a few changes :-)
    Pultra 10 cross slide


    Also thinking on making a set of indexing plates

  11. #20
    Britannicus's Avatar
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    Britannicus's Tools
    Hi there -

    yes very helpful...

    the decision to go with the Pultra and not something like the Sherline was very specifically financial - I do intend to use this really for watches and occasional small parts for things like cases and bezels, just feeling my way around and trying to work out the best approach. Your comments are very valuable - thanks :-)

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